Signaling system



Sept. 6, 1927. 1, 41,725

E.- AUSTIN siGNALING SYSTEM Filed min 9, 1 4

Inventor: Edward Austin,

His Attorney.

Patented Sept. 6, 1927.

UNITED STATES PATENT OFFICE.

EDWARD AUSTIN, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. I

SIGNALING SYSTEM.

Application filed July 9, 1924. Serial No. 725,090.

My present invention relates to high frequency signaling systems and more particularly to apparatus for use in connection with thetransmission of high.- frequency signaling currents over the conductors of a' power distribution system.

The object of my invention isto provide an efficient means .for impressing signaling currents upon a poweroline'or receiving signaling currents which. have been-transmitted over a power line which will be equally effective for different conditions of the line, that is, when the line is connected to. power apparatus such as a source of power or a powertranslating device when'it is disconnected therefrom or when the lin is grounded. V

. The novel features which I believe to be characteristic of my invention are set forth with particularity. in the appended claims- My invention itself, however, will best be understood by reference to thefollowing description, taken in connection with the accompanying drawing in which I have indicated diagrammatically one way in which my invention may be carried into etlect.

I have indicated in thedrawing'a three Dhase power distribution system comprising line conductors-1, 2 and 3 which may be connected by means of a switch 4'to a" power transformer 5 which may be employed either for supplying power to orwreceiving power from the line. A source of signaling current 6 is connected to the primary windings of transformers 7 and 8. One terminal of each of the secondaries 9 and'lO is grounded at 11 and the other terminals are connected to lines 2 and 3 through coupling condensers 12 and 13 respectively. When the transmission line is open as indicated in the drawing or when the switch 4 is closed during the normal operation of the system the signaling currents are fed to the conductors 2 and 3 in shunt, which is a desirable condition of operation.

It is frequently found desirable to ground a transmission line when it is not in operatron. In signaling systems of the present type a previously arranged this has interrupted the operation of the signaling system or necessitated a switching operation in the signal current supply system. This disadvantage is eliminated in the system which I have illustrated. Contacts 14 are provided for the switch 4 so that when the switch is Dlied directly to the two lines in series giving the most eflicient operation possible.

While the system described operates normally between two of thetra-nsmission con ductors'it-s operation will not-be interrupted if one of the conductors should become grounded at a distant point as it-will then operate between the good conductor and ground.

The transformer secondaries 9 and 10 should have a comparatively low impedance at the frequency of the power current. This requirement may be readily metby the design of the transformers, as for example'by the use of resonance transformers having the primary or the secondary tuned or havmg both primary and secondary tuned. I have indicated condensers 15 for tuning the secondaries. Drainage coils 16 having high impedance for signaling frequencies but low impedance for the power frequency may also be provided for protective purposes;

I have referred to the element 6 as a source of signaling currentbut this may also be a receiving apparatus.

While I have shown and described only one form of my invention it is apparent that many modifications therein may be made without departing from the scope thereof as set forth in the appended claims.-

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The combination in a signaling system of a power distribution systemcomprising transmission conductors and switching means for connecting an electric power apparatus to said conductors. disconnecting said a parat-us from said conductors or grounding said conductors when said conductors are disconnected from said apparatus, a source of signaling current and means for supplyin; signaling current to said conductors under any of said conditions of said switching means. I

2-. The combination in a signaling system of a power distribution system comprising transmission conductors and switching means for connecting an electric power apparatus to said conductors. disconnecting said apparatus from said conductors or grounding said conductors when said conductors are disconnected from said apparatus, a source of signaling current and means for supplying signaling current in shunt to two ofsaid conductors under one condition of said 6 switching means and in series with said conductors under another condition of said switching means.

3. The combination in a signaling. system of a power distribution system comprising transmission conductors and switching means for connecting an electric power apparatus tosaid conductors,' disconnecting said apparatusf-from said conductors or grounding saidmonductors' when said conductors are disconnected from said apparatus, a source of si'gn'aling'currentnnd means for supplying signaling current in'shunt to two ofsaid conductors when the power system is operatingrnormally and in series with one of said ingssignalin'gf current inshn'n-t totwo of said conductors when: they are connected to or disconnected from the-power apparatus and inn-series with-"one of said conductors when p grounded by said switching means.

"" :b'v-Thecombination in a signaling system of a power distribution system comprising transmission conductors and switching means for; connecting *an electric power apparatus 40 to said conductors. disconnecting'said appa- 'ratus from ,said conductors or grounding said conductors when said conductors are disconnectedfrom'said apparatus, a source of'signali'ng current and means for supplying signaling current to two of said conduotors through coupling condensers when the power system is operating normally and directly to said conductors when grounded by said switching means.

conductors when grounded by said switching meeting said apparatus from said conductors or grounding said conductors when said conductors are disconnect-ed from said apparatus. a source of signaling currents, a pair of transformers having their primaries connected in series to said source and their secondaries connected in series through coupling means between two'of said power conductors, said switching means being adaptedto short circuit said coupling means when said conductors are grounded and aground connection atthejunotion point of the two secondaries. v v

7, The combination in a signaling system of a power distribution system comprising a plurality of power transmission conductors,

means whereby an electric power apparatus may be connected to said conductors. a source of signaling"currents. a pair of trans formers 'havingthei'r primaries connected in series to said source and their secondaries connected in series the two outer terminals of said secondaries being connected through coupling condensers to two of said power conductors and a direct ground connection at the iunction point of the two secondaries.

8. The combination in a signaling system of a power distribution system comprising a pluralityof power transmission conductors, a source of signaling currents, a pair of transformers having their primaries connected in series to said source and their secondaries connected in series between two of said'power conductors through coupling condensers and a ground connection at the junction; point of the two secondaries, and switching means for short circuiting said condensers and connecting the transmission conductors to ground through said secondaries when no power is on said transmission conductors.

In witness whereof, I have hereunto set my hand this 8th day'of July, 1924.

EDlVARD AUSTIN. 

